The present invention relates to a process for the production of a cation exchange diaphragm comprising cation exchanger groups and the diaphragm obtained by this process. It also relates to the use of this diaphragm as a solid electrolyte for the production of hydrogen by the electrolysis of water.
In this application, electrolysis is performed within the diaphragm which is swollen by water and which ensures the sealing between the anodic and cathodic compartments in which are respectively evolved oxygen and hydrogen. In the art, reference is made to solid polymer electrolyte or "S P E" processes.
The anode and the cathode can be formed by the deposition of a conductive layer for electric current on each of the two faces of the diaphragm, the two layers forming the electrodes being connected to the terminals of a power supply.
When a potential difference is applied to the electrodes:
in contact with the anode the water is decomposed as follows: EQU 2H.sub.2 O .sub.4H.sup.+ +4e.sup.- +O.sub.2
in contact with the cathode the evolution of hydrogen as follows: EQU 4H.sup.+ +4e.sup.- 2H.sub.2
The existing exchange diaphragms of the present type do not simultaneously have a sufficiently high exchange capacity, a sufficiently low electrical resistance, a sufficiently high swelling in water and a permeability to gases, particularly H.sub.2 and O.sub.2 which is sufficiently low to meet practical requirements. Moreover, their chemical inertia is not always satisfactory.